The overall goal of this Program Project is to produce an interpretable brain map of cocaine action in human beings using functional magneticresonance imaging (fMRI) as a principal tool. In Project 1, we test the hypothese that the effects of cocaine on the brain relevant to its reinforcing properties and to early post-cocaine dysphoria can be specifically imaged by alterations in fMRI signal; that cocaine dependence will alter the way in which subsequent cocaine administration activates the brain; and that the functional anatomy of hyman cocaine craving will reflect activation of a subset of the regions activated directly by cocaine. We have chosen to develop fMRI technology to study the human neurobiology of cocaine action because subjects will not be exposed to ionizing radiation or injected constrast material making longitudinal studies feasible, and because fMRI offers better spatial (sub-millimeter) and temporal (10 Hertz) resolution than other available tomographic imaging techniques.